During transmission of drive power from an engine to a transmission through a clutch apparatus used hitherto in an automobile, rattling meshing noise is generated from the gears of the transmission due to non-uniform rotation of the engine especially when the engine is idling, that is, when the gears of the transmission are placed in a no-loaded condition.
Such a phenomenon is attributable to the fact that a variation of transmitted torque is directly transmitted to the transmission because the idling torque at the time of generation of such rattling meshing noise in the transmission is very small and the torsion spring acts as a rigid body.
Also, because of the provision of the backlash between the gears of the transmission, the gears collide against each other to act as a source of such rattling meshing noise. To deal with such a problem, a transmission type has been proposed in which an auxiliary gear is additionally associated with each of the gears to provide a backlash-less mechanism. However, the proposed transmission type is not commonly presently employed due to the complex structure and expensiveness of the apparatus. It is thus the present status that any countermeasure has not yet been taken since rattling meshing noise as described above is not heard during driving because of the loud background noise.